This type of lamp is generally known, as is evident from the brochures of lamps with trade names such as PL, PLC, Dulux, 2D and Lynx. The invention also relates to a lampholder assembly for one or more loop-, u- or pi-shaped gas discharge or fluorescent lamps with a single lamp cap, to be electrically connected to a ballast, a starter belonging to the lamp and the electrical contacts of the electrical power supply.
The invention is of special importance to those lighting fixtures, or parts thereof, with which the lamp and ballast and, if required, the relative starter are mounted together.
The pi-shaped gas discharge or fluorescent lamp comprises two or more glass fluorescent tubes, located parallel to one another, or in any spatial relationship, and joined together at one or both ends of the glass fluorescent tubes, so that one continuous glass fluorescent tube is formed, at least both ends of which are connected with a single lamp cap, which lamp cap is provided with at least two electrical pin or similar contacts for fitting into the lampholder.
The loop- or u-shaped gas discharge or fluorescent lamp comprises one or more loop- or u- shaped glass fluorescent tubes, of which at least the ends are connected with a single lamp cap, whereby the lamp cap is provided with at least two electrical pin or similar contacts for fitting into the lampholder.
The single lamp cap or base of the loop-, u- or pi-shaped gas discharge or fluorescent lamp is usually provided with an integrated starter. When the lamp cap does not have an integrated starter, however, the loop-, u- or pi-shaped gas discharge or fluorescent lamp has to be electrically connected with a separate starter accessory, for which the lamp cap is provided with two additional electrical pin or similar contacts. It is evident that the invention relates to lampholders for any shape and size of the earlier described lamp cap and for any shape and size of the loop-, u- or pi-shaped gas discharge or fluorescent tubes and for any given spatial relationship of the lamp cap and the fluorescent tube or tubes connected to it. The described lamp can also be provided with additional electrical contacts for power control.
The loop-, u- or pi-shaped gas discharge of fluorescent lamp with a single lamp cap, hereafter called the PL lamp or lamp, is obtainable on the market in different designs and under various trade names, as previously mentioned. In order to connect the PL lamp, with integrated or separate starter, to the electrical power supply a ballast must be incorporated, in accordance with the relative connecting diagram. On those ballasts which have been developed and put on the market by various manufacturers for this purpose, one or two, and in the future possibly more, PL lamps can be connected to each ballast, in accordance with the relative connecting diagram. The ballast can have any function.
The invention is also of importance for the lighting fixtures, or parts thereof, with which the lamp and ballast and any starter accessory are mounted together with a reflecting or backing plate, whether or not constructed to be combined as heatshield and a possible housing for the ballast.
In existing lampholders, according to the current state of the art, the PL lamps are fitted into the lampholder by means of a lamp cap with electrical pin contacts, where the relative connections between PL lamp, or PL lamps, any necessary starters, ballast and electrical power supply are effected by wiring in accordance with the relative connecting diagram, where for the connection to the PL lamp the existing lampholders only function as an intermediary connecting device.
The aforementioned procedure and method for connecting the PL lamps, ballast and any starters to the electrical power supply does provide a problem, in that the wiring has to be done in accordance with a relative connecting diagram.
Another drawback of existing lampholders, according to the current state of the art, is that the various electrical and any optical parts are mounted separately in the lighting fixtures, or parts thereof, and are mechanically fastened, which entails the use of mechanical aids, such as clamps and screws, all of which implies a considerable amount of extra work in addition to the above wiring procedure.
A disadvantage of lighting fixtures with existing lampholders is that the internal connecting elements are too easily visible. These problems have a detrimental effect on the using of the energy saving PL lamp, as opposed to the incandescent lamp which does not have these drawbacks. Another specific disadvantage of the existing lampholders for PL lamps, at present available on the market, is that because of a two-sided clamping of a single lamp cap, through a spring in the lampholder, the lamp cap can become slightly out of alignment in the lampholder and a parallel mounting with the possible use of a reflecting or backing plate is difficult and requires additional mechanical aids.